How to add more brightness to my current LED circuit?

Hi everyone, Which component should i use to boost up the brightness of my circuit. I'm using this my circuit as my "moon light" for my silver arowana.My circuit. I'm actually used the help ledcalc.com/#calc for my circuit. The power source for my circuit is 12v adapter ,500 mA, 50 hz and 13 VA (note, i don't want to change to a super bright led, preferred using my current led) Thank you.

For most standard Led's 20Ma is around the safe operating limit, so the answers already given hold true. If you go beyond this point the device dissipates more power in the Led and heating causes failure. However you can experiment with higher current and pulsing them at a higher frequency . By switching them off and on rapidly known as PWM... reduces the heating effect and may give you the results you are seeking!! I have Led circuits using this technique but it's purely trial and error, otherwise high brightness Led's are the answer.